Aqueous Ammonia Pre-treatment of Wheat Straw: Process Optimization and Broad Spectrum Dye Adsorption on Nitrogen-Containing Lignin

Mika Henrikki Sipponen*, Monika Osterberg

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
78 Downloads (Pure)

Abstract

Biorefineries need cost-efficient pretreatment processes that overcome the recalcitrance of plant biomass, while providing feasible valorization routes for lignin. Here we assessed aqueous ammonia for the separation of lignin from hydrothermally pretreated wheat straw prior to enzymatic saccharification. A combined severity parameter was used to determine the effects of ammonia concentration, treatment time and temperature on compositional and physicochemical changes [utilizing elemental analysis, cationic dye adsorption, FTIR spectroscopy, size-exclusion chromatography (SEC), and P-31 nuclear magnetic resonance (NMR) spectroscopy] as well as enzymatic hydrolysability of straw. Pretreatment at the highest severity (20% NH3, 160 degrees C) led to the maximum hydrolysability of 71% in a 24 h reaction time at an enzyme dosage of 15 FPU/g of pretreated straw. In contrast, hydrolysabilitiac remained low regardless of the severity when a low cellulase dosage was used, indicating competitive adsorption of cellulases on nitrogen-containing lignin. In turn, our results showed efficient adsorption of cationic, anionic and uncharged organic dyes on nitrogen-containing lignin, which opens new opportunities in practical water remediation applications.

Original languageEnglish
Article number545
Number of pages14
JournalFrontiers in Chemistry
Volume7
DOIs
Publication statusPublished - 2 Aug 2019
MoE publication typeA1 Journal article-refereed

Keywords

  • biorefinery
  • environment
  • lignocellulose
  • plant biomass
  • sustainable materials
  • water purification
  • MOISTURE ANHYDROUS AMMONIA
  • ENZYMATIC-HYDROLYSIS
  • OXIDATIVE AMMONOLYSIS
  • STRUCTURAL-CHANGES
  • TECHNICAL LIGNINS
  • CARBOHYDRATE COMPLEXES
  • SACCHARIFICATION
  • BIOMASS
  • ACID
  • DELIGNIFICATION

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